Fix possible double free when hiding a window

There was a race condition between the gui and the wayland event thread
which could lead to double freeing the QWaylandShmBackingStore's frame
callback. Protect the wl_callback_destroy calls using a mutex.

Change-Id: Ia70ebac208a6d4450328ba5254a850be26d84d6d
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/client/qwaylandshmbackingstore_p.h b/src/client/qwaylandshmbackingstore_p.h
index 1212e52fe..c0d730dee 100644
--- a/src/client/qwaylandshmbackingstore_p.h
+++ b/src/client/qwaylandshmbackingstore_p.h
@@ -47,6 +47,7 @@
 #include <qpa/qplatformbackingstore.h>
 #include <QtGui/QImage>
 #include <qpa/qplatformwindow.h>
+#include <QMutex>
 
 QT_BEGIN_NAMESPACE
 
@@ -106,6 +107,7 @@ private:
     QWaylandShmBuffer *mBackBuffer;
     bool mFrontBufferIsDirty;
     bool mPainting;
+    QMutex mMutex;
 
     QSize mRequestedSize;
     Qt::WindowFlags mCurrentWindowFlags;